Gear having window holes, and method and apparatus for manufacturing the same

ABSTRACT

A gear having window holes, and method and apparatus for mafufacturing the same in which by depressing partially one end surface of a primary formed article, a plurality of concaves for the window holes is formed at the one end surface in an axial direction of the primary formed articles, a plurality of projections are extruded from the other end surface thereof and tooth forms preformed at an outer peripheral wall of the primary formed article is thrown out in radial direction thereof, and the gear is formed by cutting the plurality of projections extruded from the other end surface thereof.

TECHNICAL FIELD

[0001] This invention relates to gears having window holes such as a mulcher cone synchro mesh type clutch gear used for a manual transmission for automobile and a method and apparatus for manufacturing the above described gears.

TECHNICAL BACKGROUND

[0002] A window hole of the gears having window holes are conventionally formed by forming a circular hole by drilling and reamer process, by boring by milling cutter and broaching or by blanking by press.

[0003] Drilling and reamer process need much expense for equipments for these processes and consumable tools and moreover forms of window holes are limited to circular holes. Therefore degrees of freedom of a diameter of a circular hole process and so on are restricted according to a diameter of a clutch gear.

[0004] Moreover, because the clutch gear and the circular hole are formed in different process, it is difficult to secure an accuracy of a hole phase i.e. the pitch of holes against the clutch gear.

[0005] Furthermore, because cutting scraps attach and weld flashes occur, it is difficult to secure a quality of uniform products.

[0006] In milling cutter and broaching, forms of window holes are not limitted to circular holes, but those process have problems that equipments such as consumption of equipments and tools specific to cutting, inefficiency, occurrence of cutting scraps and weld flashes, difficalty of securing hole phases against the clutch gear and requirement of process for elapse the clearance due to clearance of tools. Therefore, in those processes, products often have defect in strength.

[0007] Compared to those processes, in blanking by press machining time is shorter and forms of window hole are free. Therefore, blanking by press is good-suited to mass production.

[0008] Window holes formed by blanking by press have weld flash in a blanking direction. Therefore, it is necessary to rework by cutting to delete the weld flash after blanking and a structure of a die for blanking is complex in order to delete the weld flash.

[0009] Furthermore, cutting for the reworking is an interrupted cutting. Therefore, tool life is short, window holes are limited to penetrated holes and it is difficult to maintain a uniform tooth form due to a difference of pressure strength between a tooth form formed near by the window hole and a tooth form formed far from the window hole, while blanking.

DISCLOSURE OF THE INVENTION

[0010] The inventor of the present invention has paid attention to a first technical concept of the present invention that by depressing partially one end surface of a primary formed article, a plurality of concaves for the window holes are formed at the one end surface in an axial direction of the primary formed articles, the plurality of projections are extruded from the other end surface thereof and tooth forms preformed at an outer peripheral wall of the primary formed article is thrown out in radial direction thereof.

[0011] The inventor of the present invention also has paid attention to a second technical concept of the present invention to cut a plurality of projections extruded from the other end surface thereof.

[0012] Further, the inventor of the present invention has paid attention to a third technical concept of the present invention that a plurality of concaves for window holes are formed by cutting.

[0013] Based on these technical concepts, the inventor of the present invention has made further extensive studies and developments and has achieved the present invention.

[0014] It is an object of the present invention to keep effects on tooth forms to a minimum, to spread the degree of forms of window holes and to improve the precision.

[0015] A gear having window holes of the present invention (the first invention described in claim 1), in which by depressing partially one end surface of a primary formed article, a plurality of concaves for the window holes are formed at the one end surface in an axial direction of the primary formed articles, a plurality of projections are extruded from the other end surface thereof, and tooth forms preformed at an outer peripheral wall of the primary formed article is thrown out in radial direction thereof.

[0016] A gear having window holes of the present invention (the second invention described in claim 2) according to the first invention, in which the gear is formed by cutting the plurality of projections extruded from the other end surface thereof.

[0017] A gear having window holes of the present invention (the third invention described in claim 3), in which by depressing partially one end surface of a primary formed articles, a plurality of concaves for window holes are formed at one side surface in an axial direction of the primary formed articles, a plurality of projections are extruded from the other the surface thereof, and tooth forms preformed at an outer peripheral wall of the primary formed articles is thrown out in radial direction thereof.

[0018] A method for manufacturing a gear having window holes of the present invention (the fourth invention described in claim 4), which comprises a step of depressing partially one end surface in an axial direction of a primary formed articles, whereby a plurality of concaves for the window holes are formed at the one end surface in an axial direction of the primary formed articles, a plurality of projections are extruded from the other end surface thereof, and tooth forms preformed at an peripheral wall of the primary formed article is thrown out in radial directions thereof.

[0019] A method for manufacturing a gear having window holes of the present invention (the fifth invention described in claim 5) according to fourth invention, which comprises a step of cutting plurality of projections extruded from the other end surface thereof to form the gear.

[0020] A method for manufacturing a gear having window holes of the present invention (the sixth invention described in claim 6) according to fifth invention, which comprises steps of cutting a plurality of projections extruded from the other end surface thereof just before reaching a bottom of the caves and forming window holes with bottom.

[0021] A method for manufacturing a gear having window holes of the present invention (the seventh invention described in claim 7) according to the fifth invention, which comprises steps of cutting a plurality of projections extruded from the other end surface thereof until reaching a bottom of the caves and forming penetrated window holes.

[0022] A method for manufacturing a gear having window holes of the present invention (the eighth invention described in claim 8), which comprises a step of depressing partially one side surface of the primary formed article, whereby plurality of concave for poles is formed at the one side surface of the primary formed article, plurality of projections is extruded from the other side surface thereof, tooth forms preformed at an peripheral wall is thrown out in radial directions thereof and plurality of projections is cut to form the gear.

[0023] An apparatus for manufacturing a gear having window holes of the present invention (the ninth invention described in claim 9), which comprises a device for depressing partially one end surface in an axial direction of a primary formed articles, whereby plurality of concave for the window holes is formed at the one end surface in an axial direction of the primary formed article, plurality of projection is extruded from the other end surface thereof, and tooth forms preformed at an peripheral wall of the primary formed article is thrown out in radial direction thereof.

[0024] An apparatus for manufacturing a gear having window holes of the present invention (the tenth invention described in claim 10) according to the ninth invention, which comprises a forging device for depressing partially one end surface in an axial direction of a primary formed article, plurality of projection is extruded from the other end surface thereof and tooth forms preformed at a peripheral wall is thrown out in radial direction thereof.

[0025] An apparatus for manufacturing a gear having window holes of the present invention (the eleventh invention described in claim 11) according to the tenth invention, in which the forging device comprises tooth forms for forming tooth forms at an inner circumferential wall, a drag having counter punches for forming cave for poles at a bottom thereof and a cope having concaves formed for escape of pads in portions corresponding to the counter punches.

[0026] An apparatus for manufacturing a gear having window holes of the present invention (the twelfth invention described in claim 12) according to the eleventh invention, in which the drag comprises tooth forms for forming tooth forms at an inner circumferential surface of a cavity, ejectors are arranged at a center of a bottom part of the cavity and are able to go up and down through knockout pins and counterpunches stand around the ejectors in order that the counter punches is interposed in a nib formed on a nib booth.

[0027] An apparatus for manufacturing a gear having window holes of the present invention (the thirtieth invention described in claim 13) according to the twelfth invention, in which the clump of punches comprising an inner punch, a center punch, and an outer punch is concentrically arranged around a mandrel located in the center of the cope, and these are clumped with a cope clamp ring and are assembled to a body part of the cope.

[0028] An apparatus for manufacturing a gear having window holes of the present invention (the fortieth invention described in claim 14) according to the thirtieth invention, in which concave portions for escape of the pads are formed in a portion, corresponding to the counterpunch 7 of the drag, of the center punch of the cope and tooth forms corresponding to the tooth forms for forming tooth forms formed on the inner circumferential surface of the cavity are formed at the outer punch.

[0029] An apparatus for manufacturing a gear having window holes of the present invention (the fiftieth invention described in claim 15) according to the fourteenth invention, in which there is no phase lag between the tooth forms for forming tooth forms formed on the inner circumferential surface of the cavity and the tooth forms formed at the outer punch.

[0030] In the gear having window hole according to the first invention having the above described construction, wherein by depressing partially one end surface of a primary formed article, plurality of concaves for the window holes are formed at the one end surface in an axial direction of the primary formed articles, a plurality of projections are extruded from the other end surface thereof, and tooth forms preformed at an outer peripheral wall of the primary formed article is thrown out in a radial direction thereof. Accordingly the present invention has such effects to restrain influences on tooth forms to minimum, to enlarge the degree of freedom of profile of window holes and to improve the precision or accuracy.

[0031] In the gear having window hole according to the third invention having the above described construction, wherein by depressing partially one end surface of a primary formed articles, a plurality of concaves for window holes are formed at one side surface in an axial direction of the primary formed articles, a plurality of projections are extruded from the other the surface thereof, and tooth forms preformed at an outer peripheral wall of the primary formed articles is thrown out in radial direction thereof. Accordingly the present invention has such effects to restrain influences on tooth forms to minimum, to enlarge the degree of freedom of profile of window holes and to improve the precision or accuracy.

[0032] The method for manufacturing the gear having window holes according to the fourth invention having the above described construction, in which comprises a step of depressing partially one end surface in an axial direction of a primary formed articles, whereby a plurality of concaves for the window holes are formed at the one end surface in an axial direction of the primary formed articles, a plurality of projections are extruded from the other end surface thereof, and tooth forms preformed at an peripheral wall of the primary formed article is thrown out in radial directions thereof.

[0033] Accordingly the present invention has such effects to restrain influences on tooth forms to minimum, to enlarge the degree of freedom of profile of window holes and to improve the precision or accuracy.

[0034] The method for manufacturing the gear having window holes according to the sixth invention having the above described construction, which comprises steps of cutting a plurality of projections extruded from the other end surface thereof just before reaching a bottom of the caves and forming window holes with bottom. Accordingly the present invention has such effect to make it possible to provide gears with window hole with bottoms.

[0035] The method for manufacturing the gear having window holes according to the seventh invention having the above described construction, in which comprises steps of cutting a plurality of projections extruded from the other end surface thereof until reaching a bottom of the caves and forming penetrated window holes. Accordingly the present invention has such effect to make it possible to provide gears with penetrated window hole.

[0036] The method for manufacturing the gear having window holes according to the eighth invention having the above described construction, in which comprises a step of depressing partially one side surface of the primary formed article, whereby plurality of concave for poles is formed at the one side surface of the primary formed article, plurality of projections is extruded from the other side surface thereof, tooth forms preformed at an peripheral wall is thrown out in radial directions thereof and plurality of projections is cutted to form the gear. Accordingly the present invention has such effects to restrain influences on tooth forms to minimum, to enlarge the degree of freedom of profile of window holes and to improve the precision or accuracy.

[0037] The apparatus for manufacturing the gear having window holes according to the ninth invention having the above described construction, in which comprises a device for depressing partially one end surface in an axial direction of a primary formed articles, whereby plurality of concave for the window holes is formed at the one end surface in an axial direction of the primary formed article, plurality of projection is extruded from the other end surface thereof, and tooth forms preformed at an peripheral wall of the primary formed article is thrown out in a radial direction thereof.

[0038] Accordingly the present invention has such effects to restrain influences on tooth forms to minimum, to enlarge the degree of freedom of profile of window holes and to improve the precision or accuracy.

[0039] The apparatus for manufacturing the gear having window holes according to the tenth invention having the above described construction, in which comprises a forging device for depressing partially one end surface in an axial direction of a primary formed article, plurality of projection is extruded from the other end surface thereof and tooth forms preformed at a peripheral wall is thrown out in radial direction thereof. Accordingly the present invention has such effects to restrain influences on tooth forms to minimum, to enlarge the degree of freedom of profile of window holes and to improve the precision or accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

[0040]FIG. 1 is a sectional view showing an apparatus for manufacturing gears having window holes according to the embodiment of the present invention;

[0041]FIG. 2 is an illustrative view illustrating a step of setting the primary formed article according to the embodiment of the present invention;

[0042]FIG. 3 is an illustrative view illustrating a molding process according to the embodiment of the present invention;

[0043]FIG. 4 is an illustrative view illustrating a final step of molding process according to the embodiment of the present invention;

[0044]FIG. 5 is an illustrative view illustrating a unmold process according to the embodiment of the present invention; and

[0045]FIG. 6 is an illustrative view illustrating forms of products of window holes with bottoms and penetrated window holes according to the embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0046] The best mode for carrying out the invention is described with reference to the accompanying drawings.

Embodiment

[0047] Gears having window holes, and method and apparatus for manufacturing the same according to the embodiment of the present invention, as shown in FIGS. 1-5, in which by depressing partially one end surface of a primary formed article, a plurality of concaves for the window holes are formed at the one end surface in an axial direction of the primary formed articles, a plurality of, projections are extruded from the other end surface thereof, tooth forms preformed at an outer peripheral wall of the primary formed article is thrown out in radial direction thereof, and the gear is formed by cutting the plurality of projections extruded from the other end surface thereof.

[0048] Gears having window holes, and method and apparatus for manufacturing the same according to the embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0049]FIG. 1 is an illustrative view illustrating an apparatus for manufacturing the gears. 1 is a drag, and 2 is a cope. The drag 1 comprises a tooth forms 4 for forming tooth forms on an inner circumferential surface of a cavity 3, ejectors 6 are arranged at a center of a bottom part of the cavity 3 moving up and down through knockout pins 5 and counterpunches 7 stands around the ejectors 6 with accommodated in a nib 9 formed on a nib booth 8.

[0050] The cope 2 comprises a clump of punches comprising an inner punch 11, a center punch 12, and an outer punch 13 is concentrically arranged from inside thereof around a mandrel 10 located in the center of the cope, and these are clumped with a cope clamp ring 14 and are assembled to a body part 15 of the cope.

[0051] Concave portions 16 for escape of pads as the projection are formed in a portion, corresponding to the counterpunch 7 of the drag 1, of the center punch 12, and tooth forms 17 corresponding to the tooth forms 4 for forming tooth forms formed on the inner surface of the cavity 3 are formed at the outer punch 13.

[0052] Naturally, there is no phase lag between the tooth forms 4 for forming tooth forms and the tooth forms 17.

[0053] A process of forming a primary formed article to gears having window holes by the forging device will be described. A primary formed article 18 is a ring-shaped platen, a clutch tooth 19 having a chamfer is preformed on an outer peripheral surface and on the other side face, a concave 20 is formed at a part for forming window holes.

[0054] A major diameter of the primary formed article 18 is determined to be slightly minor diameter than that of a final product. If necessary, the primary formed article 18 is treated by head end processes such as, heat treating, shot blast and bonding.

[0055] The primary formed article 18 is set the side having the concaves 20 below, and set to the drag 1 in order that there is no phase lag between the dimple 20, and the counterpunches 7 and the tooth forms 4 for forming tooth forms (FIG. 2). And then by sending the cope 2 down, the primary formed article 18 is depressed by a clump of punches, the concaves 20 are held by the counterpunches 7(FIG. 3), the counterpunches 7 are deeply compressed into the primary formed article 18 and the concave portions 21 are formed by sending the cope 2 down. The resultant pads as projections are extruded into concave portion 16 formed at the center punch 12 of the clump of punches. Accordingly material flow in radial direction thereof occurs and the clutch tooth form 19 is thrown out in radial directions thereof (FIG. 4). After depressing and sending the cope 2 up, the product is remolded by ejectors 6 (FIG. 5).

[0056] The remolded products 22 satisfy a formal measurement of product by depressing and are finished into the high precision clutch tooth by overhang stress in radial direction thereof. A metal of window hole forming part is projected from the other end surface and the stress is dispersed. Accordingly it is able to maintain a uniform form of the clutch tooth all over the round.

[0057] Raised parts 23 as projections extruded from the other end surface in the axial direction thereof forming the concave portions 21 and from the other side of surface. Accordingly, the raised parts 23 are cutted off along the other side surface by cutting.

[0058] It is able to provide a product having window holes with a bottom by cutting one end surface of the primary formed article just before touching the other end surface and it is able to provide penetrated window holes by depressing one end surface of the primary formed article until touching a bottom of the window hole (FIG. 6).

[0059] Since the concaves are formed by forging, the degree of freedom of forms increases. The clutch tooth and the concaves for window holes are worked off in the same dye. Accordingly a hole phase toward the clutch tooth is accurate. Moreover, it is able to select between two surfaces for forming concaves 21 when forming a window hole with a bottom.

[0060] According to the above described embodiment of the present invention, when forming a window hole, plurality of concaves are formed by depressing one end surface of the primary formed article. In other words, the metal corresponding to the window holes are depressed to pressurized direction and the precision of the tooth forms is improved by overhang stress in radial direction thereof. Accordingly it is able to provide high quality and good process yield products.

[0061] Moreover, because the extruded pads remains extruded to pressurized direction, it is not necessary to consider expulsion methods such as cutting weld flash and a structure of mold is not complicated. Furthermore, forms of window holes formed at products have a choice between a window hole with a bottom and a penetrated window hole by control the depth of cut.

[0062] The preferred embodiment of the present invention, as herein disclosed, are taken as an embodiment for explaining the present invention. It is to be understood that the present invention should not be restricted by this embodiment and any modifications beyond the technical idea or principle based on descriptions of the scope of the patent claims. 

What is claimed is:
 1. A gear having window holes, characterized in that by depressing partially one end surface of a primary formed article, a plurality of concaves for said window holes are formed at said one end surface in an axial direction of said primary formed articles, a plurality of projections are extruded from the other end surface thereof, and tooth forms preformed at an outer peripheral wall of said primary formed article is thrown out in radial direction thereof.
 2. A gear having window holes according to claim 1, characterized in that said gear is formed by cutting said plurality of projections extruded from said other end surface thereof.
 3. A gear having window holes, characterized in that by depressing partially one end surface of a primary formed articles, a plurality of concaves for window holes are formed at one side surface in an axial direction of said primary formed articles, a plurality of projections are extruded from the other said surface thereof, and tooth forms preformed at an outer peripheral wall of said primary formed articles is thrown out in radial direction thereof.
 4. A method for manufacturing a gear having window holes, characterized in that comprises a step of depressing partially one end surface in an axial direction of a primary formed articles, whereby a plurality of concaves for said window holes are formed at said one end surface in an axial direction of said primary formed articles, a plurality of projections are extruded from the other end surface thereof, and tooth forms preformed at an peripheral wall of said primary formed article is thrown out in radial directions thereof.
 5. A method for manufacturing a gear having window holes according to claim 4, characterized in that comprises a step of cutting plurality of projections extruded from the other end surface thereof to form said gear.
 6. A method for manufacturing a gear having window holes according to claim 5, characterized in that comprises steps of cutting a plurality of projections extruded from the other end surface thereof just before reaching a bottom of said caves and forming window holes with bottom.
 7. A method for manufacturing a gear having window holes according to claim 5, characterized in that comprises steps of cutting a plurality of projections extruded from the other end surface thereof until reaching a bottom of said caves and forming penetrated window holes.
 8. A method for manufacturing a gear having window holes, characterized in that comprises a step of depressing partially one side surface of said primary formed article, whereby plurality of concave for poles is formed at said one side surface of said primary formed article, plurality of projections is extruded from the other side surface thereof, tooth forms preformed at an peripheral wall is thrown out in radial directions thereof and plurality of projections is cutted to form said gear.
 9. An apparatus for manufacturing a gear having window holes, characterized in that comprises a device for depressing partially one end surface in an axial direction of a primary formed articles, whereby plurality of concave for said window holes is formed at said one end surface in an axial direction of said primary formed article, plurality of projection is extruded from the other end surface thereof, and tooth forms preformed at an peripheral wall of said primary formed article is thrown out in radial direction thereof.
 10. An apparatus for manufacturing a gear having window holes according to claim 9, characterized in that comprises a forging device for depressing partially one end surface in an axial direction of a primary formed article, plurality of projection is extruded from the other end surface thereof and tooth forms preformed at a peripheral wall is thrown out in radial direction thereof.
 11. An apparatus for manufacturing a gear having window holes according to claim 10, characterized in that said forging device comprises tooth forms for forming tooth forms at an inner circumferential wall, a drag having counter punches for forming cave for poles at a bottom thereof and a cope having concaves formed for escape of pads in portions corresponding to said counter punches.
 12. An apparatus for manufacturing a gear having window holes according to claim 11, characterized in that said drag comprises tooth forms for forming tooth forms at an inner circumferential surface of a cavity, ejectors are arranged at a center of a bottom part of said cavity and are able to go up and down through knockout pins and counterpunches stand around said ejectors in order that said counter punches is interposed in a nib formed on a nib booth.
 13. An apparatus for manufacturing a gear having window holes according to claim 12, characterized in that said clump of punches comprising an inner punch, a center punch, and an outer punch is concentrically arranged around a mandrel located in the center of said cope, and these are clumped with a cope clamp ring and are assembled to a body part of said cope.
 14. An apparatus for manufacturing a gear having window holes according to claim 13, characterized in that concave portions for escape of the pads are formed in a portion, corresponding to said counterpunch 7 of said drag, of said center punch of said cope and tooth forms corresponding to said tooth forms for forming tooth forms formed on said inner circumferential surface of said cavity are formed at said outer punch.
 15. An apparatus for manufacturing a gear having window holes according to claim 14, characterized in that there is no phase lag between said tooth forms for forming tooth forms formed on said inner circumferential surface of said cavity and said tooth forms formed at said outer punch. 